The invention relates to a cabling interface for a production machine in the plastics processing industry, a method for retooling such a production machine with the inventive cabling interface, a retooled a production machine, and to a method for maintaining a production machine that has been retooled with the inventive cabling interface.
U.S. Pat. No. 6,212,963, which is hereby incorporated herein by this reference for all purposes, describes a known cabling interface for a production machine in the plastics processing industry. In the production machine, a relatively large number of workpieces are produced simultaneously and with high precision in a tool with a multi-cavity injection mold. In order to keep the reject rate to a defined level, mass production processes are monitored by a plurality of piezoelectric pressure transducers. A piezoelectric pressure transducer is arranged in each cavity of the multi-cavity injection mold. The piezoelectric pressure transducer dynamically captures a progression of a pressure in the cavity in the interior of a tool and accordingly generates a highly sensitive electrical charge signal for each internal tool pressure captured. The progression of the internal tool pressure is captured in a range from 0 to 2000 bar. A sensitivity of the pressure detection is in the range from 1 to 100 pico coulombs per bar (pC/bar). A frequency of the dynamic detection of the pressure progression is in the range of a few kHz, which means that the pressure is being detected a few thousand times during each second. An operating temperature is in the range from 0° C. to 200° C. The electrical charge signals are conducted away via cables to an electrical amplifier.
However, the tool with the multi-cavity injection mold is of complex construction and a length of the cable inside the tool is therefore cable-specific. In order to be able to route the cables inside the tool simply, cables that are not electromagnetically shielded are used, and these can be cut to length on site. The electrical charge signals also do not need to be shielded by separate means from electromagnetic and electrical interference because this is assured by a housing of the tools. The unshielded cables are thus inner cables. For this reason, the tool is equipped with the cabling interface, to accommodate the inner cables individually on an inner side of the tool and to transfer the electrical charge signals of each installed inner cable to an electromagnetically shielded outer cable on an outer side of the tool. The outer cable conducts the electrical charge signals away from the tool and on to the electrical amplifier.
However, manufacturers of production machines in the plastics processing industry have identified a need for a cabling interface that can accommodate the varied technical research and industrial needs of the customers for such production machines.
For example, U.S. Pat. No. 7,880,632, which is hereby incorporated herein by this reference for all purposes, describes a further known cabling interface for a production machine in the plastics processing industry. In the production machine, multiple measurement signals of different types are conducted away via multiple inner cables. The cabling interface includes a signal converter and an output interface. The signal converter converts the measurement signals of different types into measurement signals of the same type. The measurement signals of different types are electrical charge signals from piezoelectric pressure transducers and electrical thermo-electric voltages from thermocouples. The output interface conducts the measurement signals of the same type away to a single outer cable located outside the production machine and connected to an evaluation unit located outside the production machine. The outer cable is electromagnetically shielded. The outer cable is connected to the output interface in such manner that it can be electrically and mechanically disconnected from the output interface.
A known cabling interface of such kind for a production machine in the plastics processing industry is marketed commercially by the Kistler Group of both Amherst N.Y. and Novi Mich., with type designation 1710B, and details are provided in a datasheet 960-112d-02.15. At least one piezoelectric pressure transducer per cavity conducts electrical charge signals away to the cabling interface via an inner cable. Up to eight inner cables can be connected electrically to the inner side of the cabling interface, which is the side of the cabling interface that is disposed inside the tool. The electrical charge signals are transferred from inside the tool via the inner side of the cabling interface to the side of the cabling interface that is disposed on the outer side of the tool. An outer cable that is connected to the outer side of the cabling interface so as to be electrically and mechanically detachable thereto, conducts the electrical charge signals away to an evaluation unit located outside the tool. The outer cable is electromagnetically shielded.
A very similar known cabling interface for a production machine in the plastics processing industry is marketed commercially with type designations PZ-4 and PZ-8 by RJG Inc. of Traverse City, Mich. The external dimensions for installation in production machines of types 1710B from the Kistler Group and the PZ-4 and PZ-8 from RJG Inc, are largely identical.
One of the principal objects of the present invention is to adapt a known cabling interface for a production machine of the plastics processing industry so that it can accommodate the varied technical research and industrial needs of the customers for such production machines.